This disclosure relates to a gas turbine engine synchronizing assembly. More particularly, the disclosure relates to bumpers used between a synchronizing ring and a compressor case.
Some gas turbine engines utilize variable stator vanes that are actuated about their rotational axes to improve the overall compressor characteristics. A synchronizing assembly is used to manipulate the vanes. One type of synchronizing assembly includes a synchronizing ring that is slid relative to a compressor case by actuators. Multiple bumpers are circumferentially arranged between the synchronizing ring and the compressor case to facilitate movement of the synchronizing ring throughout the changing clearances during engine operation.
In one example, the bumper is constructed from a composite polymer material. The bumper is secured to the synchronizing ring by fasteners. Typically, the composite polymer material is arranged between a head of the fastener and the synchronizing ring such that the composite polymer material is loaded under a clamping force. Over time, the composite polymer material fatigues and cracks, which requires service to the synchronizing assembly.
One example bumper assembly includes a box-like structure machined out of titanium block. The box is secured to the synchronizing ring using a discrete locating pin to prevent rotation of the box during installation of a fastener that is used to secure the bumper assembly to the synchronizing ring. The locating pin must be very precisely machined. The bumper is secured within the box using an adhesive.